Light-Based Mechanism For Optical Indicator Guides

ABSTRACT

An optical guide has at least two surfaces in serial in front of a light source in order to diffract a light beam from the light source twice. The first surface could split the light beam into several parallel light beams along a first axis, and the second surface could split the light beams into several points of light along a second axis, and so on and so forth. By rotating the surfaces relative to one another and by adjusting the distance between the diffraction surfaces, a user of the optical guide could adjust the angle of the axis points and adjust a relative distance of the points of light relative to one another. These light beams could provide convenient guides for users in a variety of applications.

This application is a continuation of U.S. Non-Provisional applicationSer. No. 15/047,500, filed on Feb. 18, 2016. This and all otherreferenced extrinsic materials are incorporated herein by reference intheir entirety. Where a definition or use of a term in a reference thatis incorporated by reference is inconsistent or contrary to thedefinition of that term provided herein, the definition of that termprovided herein is deemed to be controlling.

FIELD OF THE INVENTION

The field of the invention is optical guides.

BACKGROUND

The background description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

All publications herein are incorporated by reference to the same extentas if each individual publication or patent application werespecifically and individually indicated to be incorporated by reference.Where a definition or use of a term in an incorporated reference isinconsistent or contrary to the definition of that term provided herein,the definition of that term provided herein applies and the definitionof that term in the reference does not apply.

It is important to use accurate measurement instruments when affixing orconstructing permanent or semi-permanent structures. Rulers of varioussizes and shapes are useful for such a task, however, such systemstypically need to make physical contact with an object being measured,and oftentimes cannot easily scale to much larger or much smaller sizes.Scalable measurement devices that do not need to physically touch anobject to obtain an accurate measurement are useful to measurestructures of various sizes and locations.

U.S. Pat. No. 7,484,306 to Campanga teaches a craft ruler having a lasermodule that could be positioned anywhere along a longitudinal axis ofthe ruler. The laser module emits a beam that defines a craftingguideline on an adjacent surface, where the guideline could be adjustedto be at an angle to the straight edge of the ruler. While Campagna'ssystem is relatively scalable, Campagna's system requires a user toplace the ruler directly on top of the device requiring the guideline,which may not always be feasible.

U.S. Pat. No. 8,209,874 to Tribble teaches a construction tool systemthat users a laser to align foundational construction components, suchas frames for buildings. Tribble's laser light unit directs the laserlight in various directions—horizontal, vertical, and pivotal—and coulddiffract the laser beam using prisms, allowing a single laser beam tohit a plurality of points on a wall. Tribble's system, however, requiresa user to install prism splitters at every intersection in order tocreate a grid guide that can be followed. Installing prism splitters atevery intersection, however, requires a user to already know appropriatemeasurements before installing the splitters.

WO 2014/06564 to Boyle teaches a structured light source that projects agrid pattern onto a surface. Scenes that are projected onto the gridcould then be measured using the grid, and range information could beobtained from determining the relative sizes of relative components ofthe grid. Boyle's grid, however, needs to be projected using a beam thatis cut into a strict 90 degree grid pattern and isn't able to projectother types of patterns.

Thus, there remains a need for a system and method that improves the waylight can be used as an indicator guide.

SUMMARY OF THE INVENTION

The following description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

The inventive subject matter provides apparatus, systems, and methods inwhich an optical guide provides a grid of points on a surface of anobject. The optical guide forms the grid by placing at least twodiffraction gratings in serial to one another, such that the orientationaxis of each grating is offset from one another. Such an optical guideis referred to herein as a “multiple diffraction optical phasometrydevice” or, for only two diffraction gratings, a “double diffractionoptical phasometry device.”

The optical guide generally comprises a light source that directs a beamof light towards serialized diffraction gratings. The light source ispreferably a laser, such as a semiconductor laser, a solid state laser,a gas laser, a metal-vapor laser, a chemical laser, a dye laser, a pointlight source, a line light source, an X-ray, or even light of otherproperties, both visual and non-visual.

While the light source is preferably a laser, the light source could beany suitable light source that directs a beam of light towards thediffraction gratings such that the beam of light is diffracted multipletimes as it is split by each serialized diffraction grating. The lightsource is preferably focused towards a surface of at least one of thediffraction gratings, and is operable by a user interface, such as abutton or a switch, that activates or deactivates the light source.

Contemplated gratings include reflective gratings, passing-throughgratings, grid gratings, diffraction gratings, or any object thatexhibits diffraction phenomenon (e.g. a filament).

At least two diffraction gratings are preferably configured in serial toone another, such that a beam of light from the light source hits afirst diffraction grating to produce a first plurality of light beamsthat are spread along a first axis, and at least one of the producedlight beams then hits the next diffraction grating to produce a secondplurality of light beams that are spread along a second axis, and so onand so forth for however many diffraction gratings are set forth inserial to one another. Generally, two diffraction gratings are used,which produces a grid of points of light. Each diffraction grating ispreferably configured to split a light beam directed towards thediffraction grating into three or more light beams. The diffractiongrating could be configured in any suitable manner to split a lightbeam, for example by using a filament, slits, prisms, or angledsurfaces, but is preferably shaped to diffract substantially all photonsthat hit its surface, for example by being shaped to have triangular,sinusoidal, or even an asymmetric triangular surface. As used herein, adiffraction grating that is shaped to diffract “substantially all”photons that hit its surface is a diffraction grating that allows morethan 90% of photons that hit its surface to either pass through to theother side or reflect back towards the source of light. (i.e. not anonreflective diffraction grating with mere slits) While the diffractiongrating could be sized and disposed to split a light beam into aplurality of unevenly spaced light beams, each diffraction grating ispreferably sized and disposed to split a light beam into a plurality ofsubstantially evenly spaced light beams. As used herein, a diffractiongrating that is sized and disposed to split a light beam into aplurality of substantially evenly spaced light beams produces a seriesof light beams that are spread along an axis of a plane that, whenmeasured, differ in spacing by no more than 5% from one another, andpreferably differ in spacing by no more than 3%, 2%, 1%, 0.5% or even0.01% from one another.

An adjustment mechanism, such as adjustment mechanisms 235, 535, 635,735, 835, 935, or 1035, coupled with one or more of the diffractiongratings could be used to adjust an angle of the diffraction grating'saxis with respect to another diffraction grating's axis. Contemplatedadjustment mechanisms include hinges, gears, axles, or cam and followermatings that are used to rotate and/or turn the diffraction grating. Anangled indicator preferably shows a measurement of the angle of adiffraction grating's axis with respect to another diffraction grating.Contemplated angled indicators include markings on a protractor or asliding indicator that slides along numbers that indicate the angle ofthe axis.

An adjustment mechanism also preferably adjusts the distance of one ormore of the diffraction gratings with respect to one another, and/or thelight source itself. A position indicator preferably shows arepresentative distance between one diffraction grating and eitheranother diffraction grating or the light source. Preferably the lightsource and diffraction gratings are positioned among one another in sucha way as to ensure that the spacing between the plurality of beamsproduced by the diffraction gratings are substantially equal to oneanother. (e.g. the plurality of light beams produced by a firstdiffraction grating are spaced apart by 2 cm, and the plurality of lightbeams produced by a second diffraction grating are spaced apart by 2 cm,when measured on an object that the light beams hit) As used herein,spacings that are “substantially equal” to one another are equal to oneanother within a 5%, 3%, 2%, or preferably 1% tolerance.

A measurement device, such as a laser ruler, could be used that measuresa distance between an object that the beams of light hit and acalibration point of the optical guide (e.g. the position of thediffraction grating that is the closest to the object). The distancecould be used to determine how far apart the projected beams of lightare from one another. Preferably, a computer processor, such as computerprocessor 255 automatically calculates the spacing between projectedbeams of light as a function of the distance between the calibrationpoint and the object. In an embodiment where an adjustment mechanism isused to adjust the distance of diffraction gratings between one another,the computer typically automatically calculates the spacing as afunction of the distance between the calibration point and the object,the distance between the source of light and the first diffractiongrating, the distance between the source of light and the seconddiffraction grating, and a refractive index of each diffraction grating.The computer is preferably functionally coupled to a display andpresents a representation of the calculated spacing to the display (e.g.displays the number 1.5 in for a grid having points of light that arespaced 1.5 in. away from one another.

Various objects, features, aspects and advantages of the inventivesubject matter will become more apparent from the following detaileddescription of preferred embodiments, along with the accompanyingdrawing figures in which like numerals represent like components.

The following discussion provides many example embodiments of theinventive subject matter. Although each embodiment represents a singlecombination of inventive elements, the inventive subject matter isconsidered to include all possible combinations of the disclosedelements. Thus if one embodiment comprises elements A, B, and C, and asecond embodiment comprises elements B and D, then the inventive subjectmatter is also considered to include other remaining combinations of A,B, C, or D, even if not explicitly disclosed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic of an inventive system employing DoubleDiffraction Optical Phasometry (DDOP).

FIG. 2A show a working system employing a DDOP system.

FIG. 2B shows a close-up image of a surface of the DDOP system of FIG.2A.

FIG. 3 shows a picture and a schematic diagram of a large structuremeasured by a DDOP system.

FIG. 4A is a schematic of a filament DDOP system.

FIG. 4B shows an exemplary filament DDOP system set up in a lab.

FIG. 5A show embodiments of another DDOP system

FIG. 5B shows the DDOP system of FIG. 5A having a differing distancebetween the gratings.

FIG. 5C shows the DDOP system of FIG. 5B having yet another differingdistance between the gratings.

FIG. 6A shows an alternative DDOP system where the second grating is setat a first distance.

FIG. 6B shows a close-up of the second grating of the DDOP system ofFIG. 6A.

FIG. 6C shows a close-up of the surface of the DDOP system of FIG. 6B.

FIG. 7A shows the system of FIG. 6A, where the second grating is resetat a second distance.

FIG. 7B shows a close-up of the second grating of the DDOP system ofFIG. 7A.

FIG. 7C shows a close-up of the surface of the DDOP system of FIG. 7B.

FIGS. 8A-8D show an embodiment that contains two light sources and threegratings.

FIGS. 9A-9D show an embodiment that contains two light sources, and twogratings.

FIGS. 10A-10D show an embodiment that contains two light sources as wellas a reflective grating.

FIGS. 11A-11B show an embodiment having a first optical pattern impactedby a first line number of the gratings.

FIGS. 12A-12B show the embodiment of FIG. 11A having a second opticalpattern impacted by a second line number of the gratings.

FIG. 13 shows a schematic diagram of a system that contains onereflective grating.

FIGS. 14A-14C show an embodiment that contains a reflective grating.

FIG. 15 shows a “surface” that is formed by the ceiling of a room andone wall, with an optical pattern shown on the surface.

DETAILED DESCRIPTION

As used in the description herein and throughout the claims that follow,the meaning of “a,” “an,” and “the” includes plural reference unless thecontext clearly dictates otherwise. Also, as used in the descriptionherein, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise.

As used herein, and unless the context dictates otherwise, the term“coupled to” is intended to include both direct coupling (in which twoelements that are coupled to each other contact each other) and indirectcoupling (in which at least one additional element is located betweenthe two elements). Therefore, the terms “coupled to” and “coupled with”are used synonymously.

Unless the context dictates the contrary, all ranges set forth hereinshould be interpreted as being inclusive of their endpoints, andopen-ended ranges should be interpreted to include commerciallypractical values. Similarly, all lists of values should be considered asinclusive of intermediate values unless the context indicates thecontrary.

The recitation of ranges of values herein is merely intended to serve asa shorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g. “such as”) provided with respectto certain embodiments herein is intended merely to better illuminatethe invention and does not pose a limitation on the scope of theinvention otherwise claimed. No language in the specification should beconstrued as indicating any non-claimed element essential to thepractice of the invention.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember can be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. One ormore members of a group can be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is herein deemed to contain the groupas modified thus fulfilling the written description of all Markushgroups used in the appended claims.

It should be noted that any language directed to a computer systemshould be read to include any suitable combination of computing devices,including servers, interfaces, systems, databases, agents, peers,engines, controllers, or other types of computing devices operatingindividually or collectively. One should appreciate the computingdevices comprise a processor configured to execute software instructionsstored on a tangible, non-transitory computer readable storage medium(e.g., hard drive, solid state drive, RAM, flash, ROM, etc.). Thesoftware instructions preferably configure the computing device toprovide the roles, responsibilities, or other functionality as discussedbelow with respect to the disclosed apparatus. In especially preferredembodiments, the various servers, systems, databases, or interfacesexchange data using standardized protocols or algorithms, possibly basedon HTTP, HTTPS, AES, public-private key exchanges, web service APIs,known financial transaction protocols, or other electronic informationexchanging methods. Data exchanges preferably are conducted over apacket-switched network, the Internet, LAN, WAN, VPN, or other type ofpacket switched network.

One should appreciate that the disclosed techniques provide manyadvantageous technical effects including providing an optical guide fora user.

The inventive subject matter provides apparatus, systems, and methods inwhich an optical guide provides a grid of points on a surface of anobject.

FIG. 1 is a schematic diagram of a Double Diffraction Optical Phasometry(DDOS) system 100. A DDOS system 100 has a light source 110, a firstdiffraction grating 120, a second diffraction grating 130, and a surface140. Light source 110 could be any contemplated light source, forexample an infrared lamp, an incandescent bulb, an ultraviolet lamp, oreven a lens or mirror that reflects natural light, but is preferably alaser that emanates a concentrated band of light. In some embodiments,light source 110 could be a plurality of light sources that are aimed atthe diffraction gratings serially (for example aimed first at firstdiffraction grating 120, whose diffracted light then hits seconddiffraction grating 130). In other embodiments, light source 110 couldcomprise a plurality of light sources, where only a subset of the lightsources are activated at a time, for example a user interface (e.g. abutton or a touch screen) could be provided that allows a user toactivate either a red laser, a green laser, and/or an infrared orultraviolet light source. Light emitted by light source 110 travelsdistance 112, and is incident on first grating 120. Some of the lightthat passes through first grating 120 (the extent of how much light isallowed to pass through is called the “width”) in a first pattern,distributed along a first axis. The subset of light that passes throughfirst grating 120 then travels distance 122 and is incident on seconddiffraction grating 130. Some of the light that hits diffraction grating130 (again, the extent of how much light is allowed to pass through iscalled the “width”), which distributes the light along a second axis. Insome embodiments the first axis and second axis could be aligned withone another, but preferably the orientation of diffraction grating 130is different than the orientation of diffraction grating 120, allowingthe light that hits both diffraction gratings to be distributed alongtwo different axis. The light that passes through diffraction grating130 then travels distance 132, and illuminates surface 140, upon whichan optical pattern appears (not shown).

While system 110 shows only two gratings whose flat planes are parallelto one another, more gratings could be used to diffract light in variousways. For example, three, four, or five gratings could be used todiffract light along three or more separate axis, and the gratings donot need to be aligned to have each plane parallel to one another.Gratings could angle diffracted light along a path without departingfrom the scope of the current invention.

As used herein, a “diffraction grating” comprises any material thatdiffracts a light source along an axis, and could be periodic oraperiodic. A grating could diffract a light source along multiplewavelengths, could diffract a light source using ridges or rulings onits surface, and could diffract using dark lines that block parts of thelight from traveling through the grating. As used herein, a “surface”could be any surface upon which measurements are made.

The system creates an optical pattern which contains several elementswith certain angular relationships and distance relationships; themembership of the elements, the angular relationships and distancerelationships are changeable by changing characteristics of thecomponents, as well as by the distances (for example, distance 112,distance 122, and distance 132 among the components, as well as by theangular relationships (e.g. the angular relationship between the twogratings, the angular relationship between the front plane of lightsource 110 and the first diffraction grating, the angular relationshipbetween the plane of the second diffraction grating and the plane ofsurface 140) among the components.

FIG. 2A and FIG. 2B both illustrate a DDOP system 200 that conforms withthe schematic of FIG. 1. Light emitted from laser 210 is incident on afirst grating 220, which is split along a first axis, and is thenincident on a second grating 230. On second grating 230, a number ofbright spots refract light, and one can see the central aperture plus anumber of pairs of spectra. Second grating 230 then splits each incidentlight beam (the split beams of light from first grating 220) across asecond axis, and displays the light on surface 240 (shown here as awhite cloth erected across a wooden frame), showing an optical patternon the plane. The optical pattern 242 is shown in more detail in FIG.2B. As shown, the initial beam of light spreads across first axis 242,and spreads across second axis 244 to form an optical pattern on surface240. As a user rotates either grating 220 or grating 230, the opticalpattern splays over the surface.

(I-b) Measurement.

When measuring structures, the structures could have one or moreelements that form angles with one another, and one or more elementsthat have distance relationships that need to be measured and/ormaintained. It is useful to use optical lasers to mark such structureswith accuracy. Measuring angular relationships between elements of astructure (e.g. parallel elements, elements that meet at a right angle,elements that meet at a 45 degree angle), measuring the distance betweenelements of a structure (e.g. ensuring that one element is 5 feet fromanother element) or maintaining proportional distances (e.g. ensuringthat one element is ⅕ the distance from a second element as it is from athird element, ensuring that a first and second element are equidistantfrom a third element), could be of paramount importance As an example,consider the two structures shown in FIG. 3. In FIG. 3, a concretestructure for a building is under construction. The three vertical beams310, 320, and 330 respectively in the picture need to be parallel to oneanother and need to form equal intervals. In addition, each verticalbeam needs to be perpendicular to ground 340. Providing laser guidancesystems to ensure that the beams are parallel to one another, and areplaced in equal intervals are of paramount importance. Thus measurementsof these angular relationships and distance relationships can bemaintained using the inventive subject matter.

The characteristics of the diffractions by the gratings, the gratingsthemselves, the distances among the components, the characteristics ofthe light source(s), and the “width” of the passing through, could bealtered in order to alter the relationships among the various elementsof an optical pattern displayed on a surface.

In a contemplated method, the components of a DDOP could be set up andthe light could be switched on such that light from the light source isdiffracted through the first grating and then through the second gratingto form an optical pattern on the surface. The parameters of the opticalpattern could then be physically measured and recorded. For example, ifthe surface comprises a grid, the location of each dot on the grid couldbe recorded manually, or preferably through a light-sensitive sensorthat records where points of light having a luminosity over a thresholdnumber (e.g. 300 lumens) are. Relationships between the dots could alsobe recorded, such as a distance from one dot to another, and an angledrelationship between two sets of parallel lines formed by a series ofparallel rows dots. (which would show the angle of the first axisrelative to the second axis). While FIG. 2A shows straight rows of dots,the system could be configured to provide a curved row of dots withoutdeparting from the scope of the invention, for example using a gratingwith a curved surface or varied concentrations of material. Themeasurements parameters could then be plugged into theoretic formulas toyield measurements of the surface itself, or computational methods couldbe employed when theoretic formulas fail to yield analytic solutions.

For example, a user could measure the distance between the light sourceand the first grating, the distance between the first grating and thesecond grating, and the distance between the second grating and thesurface to determine the distance between two dots, or could measure thedistance between the light source and the first grating, the distancebetween the first grating and the second grating, and the distancebetween two dots to determine the distance between the second gratingand the surface. In some embodiments, the measured distances could beinput into a computer system coupled to the laser diffraction system inorder to calibrate the device. In other embodiments, the system could beaimed at a line scan camera that records the optical pattern splayed onthe surface. Each of the light source 110, first grating 120, secondgrating 130, and line scan camera (surface 140), could be coupled to acomputer system that detects the status of each object (e.g. whetherlight source 110 is on or off, the intensity of light source 110, thelocation of light source 110, the location of first grating 120, thelocation of second grating 130, the location of surface 140, theorientation of first grating 120, and the orientation of second grating130) in order to calibrate the device for use.

In some embodiments, a DDOP system could be used to measure an objectupon which the optical pattern is projected. For example, when portionsof the object (e.g. an edge of a building is aligned with a series ofdots or a line in the object is aligned with a series of dots) arealigned with portions of the optical pattern, then a user coulddetermine measurements of the object. In other embodiments, a DDOPsystem could be used to measure a component, or measure one or morerelationships among components, of the system. For example, in a DDOPsystem, the user could know the distance from the light source to thefirst grating, the orientation of the first grating, the distance fromthe first grating to the second grating, the material of the secondgrating, the orientation of the second grating, the distance from thesecond grating to a surface, and positional measurements of the opticalpattern displayed on the surface to determine the material of the firstgrating. Similarly, measurements could be determined for the distancebetween the second grating and the surface when all other parameters areknown to a computer system.

In some embodiments, an alignment of either of the gratings could berotated such that at least some of the dots in the optical patternrotate, and the object being measured could then be placed along a lineof the dots in the optical pattern to ensure that the object is in theproper place. In other embodiments, rotating one of the gratings willcause the other grating to rotate by the same amount, causing the Thenalignment could be obtained between the optical pattern and the objectbeing measured, by adjusting above-mentioned various factors.

Once alignment is obtained, measurements could computed based onparameters available from the light source 110, the gratings 120 and130, the orientations of the gratings, and the distances 112, 122, and132 between the light source, gratings, and surface, respectively. Forexample, a user could set a DDOP system to display a grid of dots wherea first axis lies on a horizontal plane and a second axis lies 40degrees from the horizontal plane, to ensure that certain devices arelined up properly. In another embodiment, a user could set up a DDOPsystem to display a grid of dots, and could line the grid of dots alongtwo intersecting planes, such as two tables or two buildings (one lineof dots along one axis, and another line of dots along another axis),and then look at the device to determine the angle of one plane againstanother plane. In that same embodiment, the user could measure thedistance of the surfaces from the DDOP, which could be plugged into acomputer system to determine the relative distance between one dot andanother dot. Contemplated mathematical formulas involved are illustratedfurther below.

(II.b) Measurement with a Calibration Grating

In one embodiment, it is contemplated that a calibration grating is usedin measurement of two dots in an optical spectrum. The calibrationgrating could be used in conjunction with any exemplary system, such assystem 100 shown in FIG. 1. The spectrum of the calibration gratingappears on the surface 140 on which the optical pattern also appears,and thus measurement is performed by comparing the calibration grating'sspectrum and the optical pattern.

The methods above could also be applied on other embodiments, such as insystem 400 depicted in FIGS. 4A and 4B.

(II) The Setup of an Embodiment and the Theoretic Formula andComputation Methods Involved in Obtaining Measurements.

FIGS. 4 and 4B depict an alternative embodiment with filament gratingsystem 400 having a light source 410, a filament 420, a filter 430, agrating 440, and a line scan camera 450. The filament is configured toexhibit diffraction phenomena based upon its material properties anddimensions. Embodiment 400 uses filament 420 as its first grating,filter 430 as its second grating, and grating 440 as its third grating.In system 400, parallel monochromatic light is diffracted first byfilament 420. Filament 420 exhibits a diffraction phenomenon when lightis incident on the filament which acts as a spatial light modulator.Filter 430 only allows bright stripes of ±m orders to pass through. Thethrough-passed bright stripes are then diffracted by grating 440 into aplurality of dots onto line scan camera 450, which replaces surface 140.Line scan camera 450 detects each dot that is splayed on the surface.

(II.a) Contemplated Methods and Theoretic Formulas are Described Below.

The filament's diffraction angle of the m-order bright stripe θ_(m) inFIG. 4A meets the condition that

$\begin{matrix}{{\sin \; \theta_{m}} = \frac{{\lambda\alpha}_{m}}{\pi \; a}} & (1)\end{matrix}$

Where α_(m) is the m-th positive solution of transcendental equationα=tan α whose positive solution set is {α=1.43π, 2.459π, 3.470π,4.479πL}.

After being diffracted by the grating behind the filter, bright stripesof ±m orders are amplified. And the departure angle of gratingdiffraction θ_(n) can be calculated by the grating equation d(sinθ_(m)−sin θ_(n))=−nλ

$\begin{matrix}{{\sin \; \theta_{n}} = {{\sin \; \theta_{m}} + \frac{n\; \lambda}{d}}} & (2)\end{matrix}$

Where d is the grating constant, n is the order of grating diffraction.Therefore the spacing between the grating diffraction's n-th stripe ofthe diameter diffraction's m-th bright stripe and the gratingdiffraction's-n-th stripe of the diameter diffraction's-m-th brightstripe is

2x=2l ₁ tan θ_(m)+2l ₂ tanθ_(n)   (3)

Where l₁ is the distance between the filament and the grating, l₂ is thedistance between the grating and the line scan camera.

Then the equation for diameter measurement based on double diffractionsis obtained by applying formula (2) and (3) to formula (4)

$\begin{matrix}{x = {{l_{1}{\tan\left( {\arcsin \frac{{\lambda\alpha}_{m}}{\pi \; a}} \right)}} + {l_{2}{\tan\left\lbrack {\arcsin\left( {\frac{\lambda \; \alpha_{m}}{\pi \; a} + \frac{n\; \lambda}{d}} \right)} \right\rbrack}}}} & (4)\end{matrix}$

The analytical solution of filament diameter a can't be obtained withthis equation, therefore numerical methods such as bisection method anditeration method are used.

In experiments, it was observed that the choosing of m and n has thefollowing tradeoff:

-   -   a. The effective measurement range is limited by the camera's        total length; thus it's not proper to allow large spacing        between stripes.    -   b. Further, it's not proper to choose a small m, for the reason        that the grating diffraction spectrum of the +m order filament        diffraction and the grating diffraction spectrum of the −m order        filament diffraction would overlap so that the bright stripes'        information could not be extracted correctly.    -   c. After these considerations, m=n=5 were chosen as practically        useful in the experiment.

(II.b) Example Equipment.

The equipment is listed below was used to setup an exemplary DDOP systemof FIG. 4B:

The light source is a He-Ne laser with wavelength of 632.8 nm. And thegrating's constant value was 20 μm.

Various filaments were produced by Chengdu Chengliang Tools Group Co.,Ltd. The respective factory nominal values of diameters were 100 μm, 120μm and 140 μm with grade of tolerance±1 μm.

The filaments were measured using Digital Microscope VHX-5000 under1000× magnification which is produced by Keyence Corporation.Measurements taken by the DDOP system for each filament were 100.2 μm,120.1 μm and 140.8 μm, respectively. And the results showed thatdifferences caused by uneven manufacturing on different locations foreach filament did not exceed ±0.3 μm.

The distance from the filament to the grating and the distance from thegrating to the line scan camera were respectively l₁=160.85 mm andl₂=80.01 mm which met the Fraunhofer diffraction condition l>>10a²/λ.

The line scan camera was produced by Teledyne DALSA, Inc. of the modelP3-80-16K40-00-R whose resolution is 16384×1, pixel size was 3.5 μm andtotal length was 57.344 mm.

(III) Characteristics of the Optical Patterns.

(III.a) The “Continuity” Characteristic of the Optical Patterns.

With the method in this inventive subject matter, an optical patternchanges when the distance between the two gratings changes; this“continuity” in forming optical patterns contrasts with phenomena suchas the Moiré Fringes where optical patterns are visible only at certainplanes such as the Talbot planes.

FIGS. 5A-5C show an embodiment 500 having a light source (not shown), afirst grating 520, a second grating 530 and a surface 540, where theposition of second grating 530 changes with respect to first grating 520and surface 540, altering the characteristics of the optical patternthat is shown on surface 540. Each of the optical patterns have a“continuity” characteristic between the different surfaces when thedistance between first grating 520 and second grating 530 changes. Thesetups in FIGS. 5A, 5B, and 5C, are each similar to the setup in FIG. 1.The salient differentiation among the three setups in FIGS. 5A, 5B, and5C is the distance between the two gratings. The three setups show thatwhen this distance changes, the optical patterns change to reflect thenew position.

(III.b) The “Relatedness” Characteristic of the Multiple Components inan Optical Pattern.

With the method in this inventive subject matter, an optical patterntypically has several visible components, and it is said that thesecomponents are “related”, in that within an optical pattern there arerows of dots, and these rows are generally parallel to each other (whenthe grating is flat and made of a material of a consistentconcentration) and are thus “related”. FIGS. 6A, 6B, and 6C show a firstsystem 600, and FIGS. 7A, 7B, and 7C show a similar system 700, whichboth have “relatedness” characteristics between both produced opticalpatterns.

FIG. 6A shows another DDOP system having a light source (not shown)aimed at a first grating 620, which passes some light to second grating630, which again diffracts the light and sends some to surface 640 inthe form of an optical pattern. FIG. 6B shows a zoomed-in portion ofFIG. 6A, and shows more details of light shining through second grating630 and onto surface 640 to form an optical pattern. FIG. 6C shows aclose-up of surface 640 which has an optical pattern with multiplecomponents that have “relatedness.”

The system 700 shown in FIG. 7A is similar to the system in FIG. 6A,however system 700 has second grating 730 rotated along the Y-Z planefor 0 degrees. FIG. 7B shows a zoomed-in portion of FIG. 7A, and FIG. 7Cshows a close-up of surface 740 having an optical pattern.

The optical pattern shown on surface 640 and on surface 740 both have“relatedness. In both the optical pattern on surface 640 and on surface740, both optical patterns feature three long parallel columns of dotsalong a first axis 642 and 742, formed by first grating 620 and firstgrating 720, respectively. However, the optical pattern of long parallelrows along second axis 644 is angled about 30 degrees, whereas thetopical pattern of long parallel rows along second axis 744 is angledabout 90 degrees. Further, the change from second axis 644 to secondaxis 744 is formed as a function of the rotation of the second grating.

A change in the orientation of one grating relative to the other gratingcan create an angled incidence, allowing a user to (a) measure the angleof an object being measured by the device and/or (b) ensure that anobject is angled appropriately with respect to another object. Forexample, a user could shine a DDOP device on an object having an anglebetween two components, aligning one row of dots along one component andanother row of dots along the second component. Then the user couldanalyze a computer system that tracks the orientation of one gratingrelative to the other grating in order to determine the angle betweenthe two components being measured. In the second embodiment, the usercould first set the orientation of one grating relative to the othergrating (e.g. a 90 degree angle or a 45 degree angle) and then aim theDDOP device at two components that need to be oriented to that anglerelative to one another. The user could then align the first componentalong the first row along a first axis while aligning the secondcomponent along the second row along a second axis. This wouldparticularly be useful in the embodiment shown in FIG. 3, which requirespillars 310, 320, and 330 to be equally spaced from one another, andperpendicular to surface 340.

(IV) Several Factors that Have Impact on the Optical Patterns.

The optical pattern in any DDOP system changes with at least thefollowing factors, either with changes in individual factors, or changesin several factors combined:

-   -   (a) the characteristics of the light source;    -   (b) the characteristics of the first grating, such as its line        number;    -   (c) the orientation of the first grating along the Y-Z plane;    -   (d) the characteristics of the second grating, such as its line        number;    -   (e) the “width” of the second grating, namely how much light        along its width is allowed to pass through;    -   (f) the orientation of the second grating along the Y-Z plane;    -   (g) the relative positioning of the light source and the first        grating, as expressed as distance in this setup, but could be        other more general positioning;    -   (h) the relative positioning of the two gratings, as expressed        as distance in this setup, but could be other more general        positioning;    -   (i) the relative positioning of the second grating to the plane,        as expressed as the distance in this setup, but could be other        more general positioning;    -   (j) the characteristics of the surface where the optical pattern        appears, such as its geometric nature—for example, that it is a        plane, or that it is a cube, or that it is of an irregular        shape.

(V) Additional Embodiments.

(V.a) Variations in the number of light sources, and different naturesof light sources.

While a DDOP system preferably has at least one light source, more thanone light source could be used without departing from the scope of theinvention. In some embodiments, two, three, four, or even more lightsources could be used.

FIGS. 8A-8D show an alternative system 800 that uses two light sources810 and 820, and three gratings 830, 840, and 850. In FIG. 8A, there isfirst light source 810, second light source 820, first grating 830,second grating 840, third grating 850, and surface 860. FIG. 8B shows ablown-up view of first light source 810, second light source 820, firstgrating 830, and second grating 840. Light from light source 810 isincident on first grating 830, and light from light from the secondlight source is incident on second grating 840. Both of the gratings areaimed at third grating 850—light from first grating 830 is shown asincident row of lights 852 on third grating 850 in FIG. 8C, and lightfrom second grating 840 is shown as incident row of lights 854 on thirdgrating 850 in FIG. 8C. As shown in FIG. 8D, an optical pattern havingtwo grids, grid 862 and grid 864, is displayed on surface 860. In thismanner, a plurality of grids could be configured to display on an objector a surface. Each optical pattern could be set to display a first rowalong a first axis, with each dot in the row spaced along a firstdistance, and display a second row along a second axis, with each dot inthe row spaced along a second distance. Such configurations areespecially useful to measure and track a plurality of objects using thesame device.

FIGS. 9A-9D show an alternative system 900 that uses two light sources910 and 920, and two gratings 930 and 940. In FIG. 9A, there is firstlight source 910, second light source 920, first grating 930, secondgrating 940, and surface 950. FIG. 9B shows a blown-up view of firstlight source 910, second light source 920, and first grating 930. Lightfrom the first light source 910 is incident on first grating 930, butlight from the second light source 920 is not incident on first grating930. Light passing through first grating 930 is incident on secondgrating 940 as incident light 942, and light from second light source920 is also incident on second grating 940 as incident light 944.Incident light 942 has been diffracted into a row of dots by firstgrating 930, whereas incident light 944 has yet to be diffracted. FIG.9C shows a close-up of second grating 940 and surface 950, and FIG. 9Dshows how two optical patterns are formed, a first is a grid opticalpattern 952, and the second is a row of dots 954.

FIGS. 10A-10D show an alternative system 1000 that contains two lightsources 1010 and 1020 as well as a reflective grating 1030. FIG. 10Ashows a first light source 1010 and a second light source 1020 bothaimed at reflective grating 1030. Reflective grating is shown as areflective grid grating, but could be any grating without departing fromthe scope of the current invention. FIG. 10B shows a close-up ofreflective grating 1030, which reflects light from light source 1010 andlight source 1020 onto a surface behind light sources 1010 and 1020,such as surface 1040, which shows how the incident light from lightsource 1010 shining on reflective grating 1030 as incident light 1032,and how incident light from light source 1020 shining on reflectivegrating 1030 as incident light 1034, is splayed into a plurality ofoptical patterns in a grid form on surface 1040. FIG. 10C shows a viewof the optical pattern displayed on a large wall 1050, while FIG. 10Dshows a close-up of the grid optical pattern displayed on large wall1050.

(V.b) Variations Line Numbers of the Gratings

FIGS. 11A-11B show a system 1100 having a first light source 1110, afirst grating 1120 with a first line number, a second grating 1130 witha second line number, and a surface 1140. FIGS. 12A-12B show a system1200 having the same first light source 1210, the same first grating1220 with a first line number, a third grating 1230 with a third linenumber different from the second line number, and a surface 1240. Asshown, the optical pattern on surface 1140 is markedly different thanthe optical pattern on surface 1240 due to the difference in linenumbers. Third grating 1230 has a smaller line number than secondgrating 1130, and the dots are spaced out further. Such properties areparticularly useful for embodiments which could use a plurality ofgrating systems for measuring a device. Preferably, the system is set upsuch that a computer system automatically switches from one grating toanother based upon a user inputting in a preferred line number.

(V.c) Variations in the Nature of the Gratings.

FIG. 13 is a schematic of a reflective grating system having lightsource 1310 that is aimed at reflective grating 1320, which bothreflects and diffracts the light towards diffraction grating 1330, whichthen directs refracted light towards surface 1340 to form an opticalpattern.

FIGS. 14A-14C show an alternative system 1400 having a first lightsource 1410 and a second light source 1420 both aimed at reflective gridgrating 1430. The light from light source 1410 and light source 1420hits reflective grid grating 1430, and shines onto a surface behindlight source 1410. An exemplary surface 1430 is shown in FIG. 14B, whichshows the grid pattern caused by the light source 1410 and light source1420 hitting reflective grid grating 1430. In order to create a complexoptical pattern used to measure a plurality of aspects, the a user couldinsert a second grating (not shown) in between light sources 1410 and1420 and reflective grid grating 1430. The optical pattern that would beproduced is shown in FIG. 14C on surface 1440.

(V.d-b) Variations in the Orientation of the Axes of the Two Gratings.

FIG. 15 is a schematic 1500 of another alternative embodiment, havinglight source 1510, perpendicular first diffraction grating 1520, angledsecond diffraction grating 1530, and surface 1540. As shown, angledsecond diffraction grating 1530 could be angled from first diffractiongrating 1520 away from the Y-Z plane, which could be useful in systemswhere the angle of the optical spectrum needs to be adjusted slightly

(V.e) Variations in the “Width” of the Second Grating.

FIGS. 11A-11B show an embodiment 1100, and FIGS. 12A-12B show a similarembodiment 1200; the two embodiments combined illustrate that by varyingthe “width” of the second grating (namely how many bright spots areallowed to pass through), the optical patterns change accordingly. Inthe first setup, FIG. 11A, shows that the second grating allows twobright spots (the central aperture plus one spectrum) to pass through,and an optical pattern, which is two vertical columns of bright spots,can be observed as shown in FIG. 11B. In the second setup, FIG. 12Ashows the second grating allows one bright spots (the central aperture)to pass through, and an optical pattern which is one vertical column ofbright spots, can be observed as shown in FIG. 12B. These two setups,with only salient difference being the “width” of the second grating,show that the angular relationships and distance relationships betweenthese bright spots are partially dependent on the width of the secondgrating.

(V.f) Variations in the Distance Between the Two Gratings.

FIGS. 5A-5C illustrate that by varying the distance between the twogratings, the optical pattern changes accordingly. The setups in FIGS.5A, 5B, and 5C are the same to each other, with the salient differencebeing the distance between the two gratings. With a longer distancebetween the two gratings, the optical pattern has more dense dots—namelymore dots per unit length on the surface.

(V.g) Variations in the Surface.

While the surface where the optical pattern appears (e.g. surface 130 inFIG. 1) in many embodiments is a plane, it is contemplated that othersurfaces are useful, including but are not limited to:

-   -   (1) surfaces that can be described by simple geometric        functions, such as a concave or a convex.    -   (2) surfaces that cannot be described by simple geometric        functions.    -   (3) considering the interior of a room, the surface that is        formed by the ceiling and one wall.    -   (4) considering the interior of a room, the surface that is        formed by the ceiling and two neighboring walls.    -   (5) a line scan camera.

It should be apparent to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the inventive concepts herein. The inventive subjectmatter, therefore, is not to be restricted except in the scope of theappended claims. Moreover, in interpreting both the specification andthe claims, all terms should be interpreted in the broadest possiblemanner consistent with the context. In particular, the terms “comprises”and “comprising” should be interpreted as referring to elements,components, or steps in a non-exclusive manner, indicating that thereferenced elements, components, or steps may be present, or utilized,or combined with other elements, components, or steps that are notexpressly referenced. Where the specification claims refers to at leastone of something selected from the group consisting of A, B, C . . . andN, the text should be interpreted as requiring only one element from thegroup, not A plus N, or B plus N, etc.

What is claimed is:
 1. An optical guide, comprising: a first lightsource; a first surface configured to split a first light beam from thefirst light source to produce a first plurality of light beams along afirst axis, wherein the first surface has a first side and a second sideopposite to the first side, and wherein the first light beam enters thefirst side and the first plurality of parallel light beams exit thesecond side; a second surface configured to split at least one of thefirst plurality of light beams to produce a second plurality of lightbeams along a second axis, wherein the second axis changes as the secondsurface rotates, and is angled from the first axis; and an adjustmentmechanism that adjusts an angle of the second axis relative to the firstaxis along the rotation axis.
 2. The optical guide of claim 1, whereinthe first surface is configured to provide a first even spacing betweenat least three of the first plurality of light beams when the firstplurality of light beams hit an object.
 3. The optical guide of claim 1,wherein the second surface is configured to provide a second evenspacing between at least three of the second plurality of light beamswhen the second plurality of light beams hit the object, wherein thefirst even spacing is substantially equal to the second even spacing. 4.The optical guide of claim 1, further comprising a computer processorconfigured to: calculate a spacing between the second plurality of lightbeams when the second plurality of light beams hit an object; andpresent a representation of the calculated spacing.
 5. The optical guideof claim 4, wherein the computer processor is further configured to:calculate the angle of the second axis relative to the first axis; andpresent a representation of the angle.
 6. The optical guide of claim 1,wherein the second surface comprises a reflective portion.
 7. Theoptical guide of claim 1, wherein the second surface has a major surfaceparallel to a major surface the first surface; wherein the first axischanges as the first surface rotates along a rotation axis perpendicularto both the first axis and the major surface of the first surface andthe major surface of the second surface; and wherein the second axischanges as the first surface rotates along the rotation axis.
 8. Theoptical guide of claim 1, wherein the second plurality of light beamscomprise light pattern points.